Oxidative stress mitigation and the inhibition of carbohydrate-hydrolysing, lipoxygenase (15-LOX), and acetylcholinesterase enzymes by methanolic crude extracts and partitioned fractions of Rinorea dentata (P Beauv.) O Ktze. leaf and stem

ABSTRACT

Rinorea dentata (Violaceae) is a rare medicinal plant used in treating many diseases such as malaria, neurodegenerativediseases, body inflammation, and diabetes among others. The study investigated the in vitro pharmacological activitiesof crude extract and partitioned fractions from the leaf and stem parts. Antioxidant activity was evaluated usingthe ability of the crude extract and fractions to scavenge 2, 2-diphenyl-1-picrylhydrazyl radical and ferric reducingantioxidant power (FRAP). In vitro anti-inflammatory and anticholinesterase potential of the extracts, the inhibitionof α-amylase (α-AL) and α-glucosidase (α-GSD), and kinetics of enzymes inhibition were evaluated by the standardmethods. The ethyl acetate fractions (EAFs) of both leaf and stem gave the highest total phenolic content and the bestantioxidant potential in the FRAP assay. For the anticholinesterase activity, crude extract of both leaf and stem hadthe highest inhibitory activity. Leaf EAF (34.14 ± 16.69 µg/ml) had superior lipoxygenase inhibitory activity thanquercetin (54.75 ± 17.07 µg/ml) and better than the stem. The dichloromethane fraction had the best α-GSD and mildα-AL inhibitions with 204.00 ± 8.12 and 500.42 ± 2.87 µg/ml IC50 values, respectively. R. dentata leaf extract going bythe results of the investigation is a good source of antioxidant, anticholinesterase, anti-inflammatory, and antidiabeticagents for future drug development and sustainability